1. Technical Field
The present invention relates to a shape-variable optical element and an optical read/write device including the shape-variable optical element.
2. Background Art
Every optical disc drive (ODD), such as compact disc (CD), digital versatile disc (DVD) and Blu-ray disc, which are currently available in the markets, stores data in a disc by varying transmittance and reflectance of light.
Generally, data are stored in the circular plate shape of disc, and laser beam converged through a lens is reflected, refracted or penetrated on the surface of the disc, at which time the disc drive reads the data by reading a variation in the phase or polarization of the light that is changed on the surface of the disc. One of such traditional storage media is CD, and the Blu-ray disc is developed recently to store a large capacity by increasing the degree of integration in the storage area. As more information can be inputted/outputted to and from a single disc, there has been an increasing demand for optical information device with faster input/output functionality.
In the case of currently commercialized optical information devices, data is inputted or outputted using a single lens, and thus the disc needs to be spun faster in order to read and write the data faster. However, the revolving speed of the disc cannot be increased infinitely, thereby hindering the growth of large-capacity input/output technology.